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When to Plant Hubbard Squash in Lake County, CO

Hubbard squash is a large, bumpy-skinned winter squash with dense, sweet, dry flesh ideal for baking and pies. The hard shell allows storage for 6 months or more.

Lake County, Colorado is in USDA Zone 4a. The average last spring frost is June 21 and the first fall frost is August 30, giving you a growing season of approximately 70 days.

At an elevation of 7,687 feet, Lake County receives approximately 21.2 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Hubbard Squash to ensure they mature before fall.

Lake County, CO (Zone 4a) Very short season
70 days
Last Spring Frost June 21
70 growing days
First Fall Frost August 30

Lake County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 5 Transplant: Jul 7 🍅 Harvest: Oct 20 – Nov 24
Recommended (50%) ✗ May not fit
Start indoors: May 10 Transplant: Jul 12 🍅 Harvest: Oct 25 – Nov 29
Safe Start (90%) ✗ May not fit
Start indoors: May 16 Transplant: Jul 18 🍅 Harvest: Oct 31 – Dec 5

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Hubbard Squash needs ~1,348 GDD — county provides 857 GDD May not mature

Hubbard Squash Planting Timeline โ€” Lake County, CO

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors May 10 May 10 โ€“ May 24
Transplant Outdoors July 12 Jul 12 โ€“ Jul 26
Direct Sow July 5 Jul 5 โ€“ Jul 26
Harvest October 25 Oct 25 โ€“ Nov 29

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Start Indoors
June โ€”
July Transplant Outdoors Direct Sow
August โ€”
September โ€”
October Harvest
November Harvest
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

100โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4a

Growing Season

70 days

Growing Tips for Lake County

Start seeds indoors in short-season areas. Requires ample space and rich soil. Harvest when the skin is very hard and the color is deep. Cure in the sun before storing.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Hubbard Squash in Lake County, CO?

Lake County is in Zone 4a with an average last frost of June 21. Plan your Hubbard Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lake County, CO?

Lake County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 21 and first fall frost is August 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lake County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Lake County, CO. Local conditions may vary. Last updated: April 2026.